1. Field
Embodiments relate to a composition for encapsulation and an encapsulated apparatus including the same.
2. Description of the Related Art
Encapsulating an organic optoelectronic apparatus (such as an organic light emitting diode), an apparatus including photovoltaic cells, a display apparatus (such as an organic thin film transistor display), or the like, may help protect sensitive components from ambient conditions or the atmosphere (e.g., oxygen and/or moisture). Without appropriate protection, the apparatus may suffer quality deterioration. Quality deterioration may be caused by generation of dark spots. In organic light emitting diodes, water vapor may permeate the diodes and may deteriorate diode quality, e.g., quality at an interface between an anode or cathode and an organic film.
Encapsulation may be carried out by bonding a glass cap to a display apparatus using adhesives, e.g., adhesives exhibiting low water vapor permeability. In an implantation, a solid moisture getter may be inserted between a substrate and the cap to help extend the lifespan of the apparatus. Although this may be appropriate for a rigid apparatus, encapsulation using the cap may be inappropriate for an apparatus including a flexible support unit, such as a flexible display.
In addition, such encapsulation technology may not be applied to an apparatus having an insufficient space in a circuit on a substrate, as in a complementary metal oxide semiconductor (CMOS) micro-display, and may not be used for an apparatus having a large emission region to reduce the weight of the apparatus.
In cases in which encapsulation using the cap is inappropriate, “monolithic” encapsulation, e.g., an encapsulation method using a thin film exhibiting good oxygen blocking and water vapor blocking properties may be used. Materials commonly used in this type of method may include oxide dielectrics and/or nitrides, represented by SiOx, SiNx, SiOxNy and AlxOy, and may be deposited by chemical vapor deposition (CVD) or selectively deposited by plasma enhanced chemical vapor deposition (PECVD) or atomic layer deposition (ALD). These processes may be preferred over physical vapor deposition (PVD) methods, such as sputtering, which may be aggressive to organic semiconductors, e.g., causing formation of layers exhibiting unsatisfactory properties upon coating protective layers due to defects, such as generation of a large number of pinholes in the deposited layers. Plasma enhanced chemical vapor deposition and atomic layer deposition may be advantageous in that deposited layers may have a significantly small number of defects and may be extremely uniform, as compared to layers obtained by physical vapor deposition. For example, these two processes may provide excellent step coverage.